Lifting jack



' June 25, 194 0. JOHNSON 2,205,691

LIFTING JACK Filed Sept. 1, 1957 2 Sheets-Sheet l grvurMo'b 14/10 A. Jab/75w? Jime 25, 1940- A. L. JOHNSON LIFTING JACK Filed Sept. 1, 1957 2 Sheets-Sheet 2 Patented June 25, 1940 UNIT TES

LIFTIN G JACK Alvin L. Johnson, Ottawa Hills, Ohio, assignor to The American Forging & Socket Company, Pontiac, Mich, a corporation of Michigan Application September 1, 1937, Serial No. 161,881

8 Claims. (Cl.'254- 98) This invention relates to jacks but more particularly to lifting jacks such, for example, as are adapted to engage and lift the bumpers of automobiles, thereby to raise the vehicle.

An object of this invention is to produce a jack having a load-sustaining member which is movable forwardly along a bar or rod during the advancing or lifting movement and cooperates with the rod for supporting the load in the inter- 10 vals between the advancing or lifting operations, such member being adapted to cooperate with the bar for effecting the retracting or lowering movement of the load upon relative rotation of these parts.

, Another object is to produce a jack in which the load israised or advanced by recurrent lever operations and is retracted or lowered by relative rotational movements of theparts.

A further object is to produce a vehicle bumper so engaging jack which embodies a screw-threaded rod with which lever means cooperates for recurrently lifting the bumper, the construction being such that rotation of'the rod effects retracting or lowering movement of the bumper. 25 A still further object is to produce a jack for automobiles and other uses which is simple and sturdy in construction, reliable in operation, in-

expensive to manufacture, easy to assemble and contains the new and improved features of con 30 stru'ction, arrangement and operation hereinafter described. I

A still further object is to produce a jack of this character in which lifting is accomplished by lever means cooperating, with a screw-threaded 35 rod and lowering by rotation of the rod, a tensioned part of the jack yielding radially to enable advancing or lifting movement of the jack and for sustaining the load after lifting has been accomplished and also cooperating with the rod 40 upon turningmovement thereof to cause retracting or loweringof the load.

For purposes of illustration but not of limitation, embodiments of the invention are shown on the accompanying drawings in which:

45 Figure 1 is a side elevation, partly in section, of a lifting jack, the parts being shown in the position assumed during the advancing orraising step, some of the parts being broken away to show the load-sustaining nut and associated 50 parts and the manner in which the lever-actuated pawl engages the threads on the rod;

Figure 2 is a transverse sectional viewon the line Z--2 of Figure 1; Figure 3 is a fragmentary view of the upper 55 end of the screw-threaded rod showing the.op.

ting the screw threads it on the rod 82.

crating handle attached thereto for actuating the rod to lower the jack;

Figure 4 is a side elevation of an alternate form of jack in which a pair of pivotally mounted load-sustaining members are employed; and 5 Figure 5 is a fragmentary vertical sectional view showing the load-sustaining members and associated portionsof the jack.

' Referring to the drawings, the jack comprises a dome-shaped base it having a depression ii in the top to receive the rounded end of a rod l2. The rod I2 is free from connection with the base It and is adapted to rotate relatively thereto. Formed on the rod are helical screw threads It, the screw threads being buttress screw threads for a purpose which will hereinafter appear. Mounted on the rod I2 is an elongate sleeve or housing It on the upper end of which is swivelly mounted a collar 55 which rests against an annular flange it, a depending portion ll integral g with the collar engaging the flange it. Projecting laterally from the collar is an integral arm 58 which is recessed to engage an automobile bumper or the like.

Extending laterally from an intermediate portion of the sleeve M is an enlargement i 9 to which a lever arm is pivoted upon a pin 2|.

The lever arm 20 is formed with a socket Zia to receive an end portion of a handle 22. As indicated in Figure 3, the handle '22 has a bend 23 3 so that it can be used as a crank for a purpose which will hereinafter appear.

Pivoted at one end on a pin E l adjacent the pin 2! is a pawl 25 the end of which extends through an opening in the sleeve i i and engages the screw threads IS. A coil spring 25 yieldingly urges the pawl 25 into engagement with the threads I3. It will be apparent that upon swinging movement of the lever arm 20, the sleeve M is advanced step by step upwardly along the rod E2, the pawl 25 successively engaging the threads E3 on the rod for effecting this movement.

The sleeve I land load supported thereby is supported during the upward swinging movement of the lever arm 28 bya load-sustaining member 21 which is disposed in an enlargement 28 projecting outwardly from the sleeve It. The load-sustaining member 24 consists of a rectangular nut having internal screw threads iitnut is separated into parts 21a and 212) which are urged toward each other and intimately into engagement with the threads l3 by leaf springs, a leaf spring 29 being secured by a screw to the part 21a and bearing against the outer por- 55 The tion of the enlargement 28. A similar leaf spring 3| similarly connected to the part 2Tb abuts against lugs 32 extending inwardly from the walls of the sleeve I4. The upper ends of the nut parts 270/. and 211) are formed with complementary inwardly tapered portions 21c which together provide a surface slightly larger than the bore of the housing.

Within the enlargement 28 is a cavity 33 which alfords a limited amount of movement to the load-sustaining member 21 in a direction longitudinally of the rod I2. The upper portion of the cavity 33 is formed with a recess 34 into which the member 21 is adapted to fit, the tapered portion Zlc of the nut partsjll being adapted to bear against a tapered seat 340: adjacent the recess 34. It is apparent that when the sleeve i4 is advanced or moved upwardly along the rod l2 by the lever actuated pawl 25, the parts 21 and 23 yield radially and slip over the buttress threads !3 but upon release of the pawl 25 when the lever arm 20 is released or swung upwardly, the sleeve l4 rests upon and is supported by the load-sustaining member 21 which is securely held in the recess 34 and transmits the load to the threads l3; During this operation the seat 34a of the housing bears against the tapered portions 270, insuring against lateral movement between the two parts of the nut 27. In this manner it is apparent that progressive or step by step advancing movement of the sleeve M may be effected alongthe rod l2.

In order to lower or retract the sleeve Hi, the upper end of the screw-threaded rod i2 is formed with a squared opening 35 into which fits I 1y along the rod.

a similarly shaped extension 36 on the end of the handle 22. Thereupon by turning the handle 22 which in this instance serves as a crank, the rod I2 is rotated and since the load-sustaining member 21 is held in place by the load imposed upon it and due to its frictional engagement with the sleeve M, the sleeve is moved downward- In the form shown in Figures 4 and 5, the spring-tensioned lever actuated pawl 25a operates in the same manner as the pawl 25 above described. The rod [2a has buttress screw threads Ilia as above described so that the sleeve Ma is similarly advanced or raised in order to lift the rod. However, instead of a split nut, a diiferent form of load-sustaining device is employed. In this instance, a pair of opposed arms 31 are pivotally mounted at their upper ends on pins 38 carried by projections 39 of the sleeve Ma. The free ends of the arms extend through slots M in thesleeve Ma into engagement with the threads on the rod I211. The arms are urged inwardly into engagement with the threads on the rod lZa by coil springs 40 which encircle the pins 38 and abut respectively against the arms and the sleeve Ma. The rod engaging ends of the arms 3'! are threaded to correspond with the threads 53a. When; the sleeve I la, is advanced or moved upwardly along the rod l2a, the arms 31 slip over the threads and when the load is released, the arms 3'! cooperating with the threads l3a support the load.

It will be understood that the sleeve Ma is lowered or retracted by rotating the rod H11 in a manner above described, the arms 31 sustaining the load during such lowering movement.

It is to be understood that numerouschanges in details of construction, arrangement and operation may be effected without departing from the spirit of the invention especially as defined in the appended claims.

What I claim is:

1. In a jack of the character described, a rod having buttress screw threads, a load-receiving member on said rod, lever actuated spring tensioned pawl means for recurrently advancing said member, a load sustaining device carried by said member and having opposed spring tensioned internally screw-threaded parts urged into engagement with the threads on said rod, and means to impart relative rotation between said rod and load-sustaining device for retracting the latter.

2. In a jack of the character described, a rod having buttress screw threads, a load-receiving member on said rod, lever actuated spring tensioned pawl means? for recurrently advancing said member, a load-sustaining nut carried by said member internally screw-threaded to fit the threads on said rod, said nut being formed in sections separable radially away from said rod, spring means normally urging said sections toward the rod, and means to impart relative rotation between said nut and rod for retracting the nut and load-receiving member.

3. A jack including a screw-threaded rod, a load receiving member on the rod, lever actuated means for advancing said member, sectional threaded load sustaining means carried by said member and movable longitudinally thereof for engaging the screw threads of the rod, and means carried by the member which upon downward movementof the load sustaining means automatically moves and holds the sections thereof in engagement with the screw threads of the rod and which upon upward movement of the load sustaining means are released from the automatic means and are moved by the threads of the rod out of operative engagement with said threads.

4. A jack in accordance with claim 2, wherein the nut sections are movable longitudinally of 'the load-receiving member and wherein there are complementary means between the nut sections and said memberfor causing the sections to move and be held in engagement with the rod threads upon relative longitudinal movement between the nut sections and member in one direction and to be released upon longitudinal movement in a reverse direction.

5. A jack in accordance with claim 2, wherein the nut sections are movable longitudinally of the load-receiving member and wherein there are complementary means between the nut sections and said member for causing the sections to move and be held in engagement with the rod threads upon relative longitudinal movement between the nut sections and member in one direction and to be released upon longitudinal movement in a reverse direction, and wherein said complementary means consist of tapered portions receivable one within the other to have a camming action therebetween.

6. In a lifting jack, in combination with a support, a threaded shaft rotatably mounted thereupon, a load-carrying member slidable along said shaft over the threads, means including a lifting element successively engageable with said'threads as the load-carrying member moves along the shaft, said lifting element being movably mounted in said load-carrying member and arranged to ratchet over said threads to prevent reverse movement of said member, means including a lever. for actuating said lifting element to force the load-carrying member along the shaft, separate pawl means carried by said member and reacting against said threads in the same direction as said lifting element, means constantly urging said pawl means into engagement with said threads, and means for turning said shaft with relation to the pawl means, whereby said pawl means may act as a nut to react against the threads and force said member along the shaft.

7. Means as set forth inclaim 6 in which said pawl means comprises a divided nut having complementary sections movable to and from engagement with said threads, said threads being substantially of buttress form, whereby said nut sections may ratchet thereover in one direction, and

means urging said sections into engagement with the shaft.

8. Means as set forth in claim 6 in which said 

